• Journal of Advanced Marine Engineering and Technology
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• v.40 no.9
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• pp.780-785
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• 2016

Heavy oil used as ship propulsion has a serious issue regarding exhaust emission of global warming. Recently, among large-scale merchant ships are using LNG as green ships so called ech-ships. In this study, an vaporizer and pipes under cryogenic and high pressure load were considered to evaluate structural integrity according to codes. Structural analysis of the vaporizer and pipes was performed using the commercial code, ANSYS. Integrity evaluation of the vaporizer based on von Mises stress was performed in accordance with allowable stress specified in ASME Boiler & Pressure Vesssel Section VIII Division 2. To assess structural integrity of the pipes, stress components were combined and compared with ASME B31.3. The calculated stresses for all load cases are lower than allowable stresses, therefore the structural integrity of equipments are verified.

• Journal of the Korean Institute of Gas
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• v.2 no.2
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• pp.34-39
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• 1998

Demand of the clean and convenient natural gas has continuously increased with recognizing of the environment problem since liquefied natural gas was introduced in Korea. Clean fuel natural gas was supplied to each city through high tensile strength pipeline connected by welding. Grades of pipeline were divided into the high and middle pressure according to supply pressure. Pipeline was welded mainly SMA welding process due to its easy handling, the other welding process was adopted according to the constructing condition. We were examined on the microstructure variation and mechanical properties of weld metal for high pressure pipeline, API 5L X-42.

• Journal of Ocean Engineering and Technology
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• v.31 no.2
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• pp.91-102
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• 2017

Recently, a new type of LNG membrane Tank called the "KC-1 membrane LNG Tank" was developed by KOGAS (Korean Gas Corporation). It is necessary to estimate the temperature distribution of the hull structure and insulation system for this new LNG tank, as well as the BOR (Boil-Off Rate) when exposed to outside temperature conditions to ensure the integrity of the tank structure and limit LNG evaporation, from a safety evaluation point of view. In this study, temperature distribution calculations for the hull structure and insulation system of the KC1 membrane tank were compared by employing four numerical approaches under the IGC condition. Approaches 1-3 studied 2D simulations and approach 4 used a 3D numerical simulation. Approach 1 was calculated by in-house Excel VBA codes and the three other approaches utilized ANSYS Fluent. The BOR of approach 4, the 3D simulation case, for the IGC condition was 0.0986%/day.

• Korean Chemical Engineering Research
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• v.60 no.3
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• pp.371-376
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• 2022

Liquefied natural gas undergoes a process of vaporization to be supplied as city gas, which generates about 800 kJ/kg of cold energy. Currently, all of this cold energy is being dumped into the sea, resulting in a very serious energy waste from the point of view of energy recycling. In this study, a seawater desalination process that can utilize the wasted cold energy was proposed, and this process was optimized to analyze the specific power consumption and economic feasibility. As a result, the specific energy consumption of the proposed process was calculated as -5.2kWh/m³, and the production cost of the pure water was 0.148 USD/m³, confirming that it is superior to any other process developed so far.

• Plant Journal
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• v.9 no.1
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• pp.43-49
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• 2013

In this study, the natural frequency of the actual operating vertical pump in the P combined cycle power plant is measured and the cause of high vibration is determined by using fluid-structure coupled vibration theory. Choosing the vibration reduction plan suited for field conditions and using the numerical analysis verify effectiveness of the plan. The plan is applied to the actual pump and the empirical experiments are conducted.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.22 no.7
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• pp.442-447
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• 2010

FPSO (Floating Production Strorage and Offloading) method for LNG industry is efficient and facile compared to onshore NG (Natural Gas) treatment facility. Five simple natural gas liquefaction cycles for FPSO are presented and simulated in this paper. SMR (Single Mixed Refrigerant) cycle, SNE (Single Nitrogen Expander) cycle, DNE (Double Nitrogen Expander) cycle, PNE (Precooled Nitrogen Expander) cycle, and PDNE (Precooled Double Nitrogen Expander) cycle are compared. Simple analysis results in this paper show that precooling process and adding an expander in the liquefaction cycle is an effective way to increase liquefaction efficiency.

• Nuclear industry
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• v.38 no.2
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• pp.13-27
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• 2018

재생에너지의 활용 가능성이 제한적이고 인구 밀도가 높은 대한민국의 현실을 놓고 볼 때, 원자력은 온실가스 배출 및 공해를 줄이면서도 충분한 전력을 생산하여 공급해줄 수 있는 가장 신뢰할만한 발전 수단이다. 그러나 한국 정부는 원전과 석탄발전소를 단계적으로 폐쇄하고 이를 대체하기 위해서 다양한 재생에너지를 늘리겠다는 정책을 확고하게 고수하고 있다. 그렇지만 에너지 생산 수단을 전환하겠다는 이 정책의 주요 목표는 액화천연가스(LNG) 발전을 대체 수단으로 삼고 있다. 그 이유는 다른 재생에너지들의 대규모 생산 수단을 개발하는 데는 기술적이고 경제적인 난제들이 걸림돌이 되기 때문이다. 그러므로 미래의 에너지 정책을 결정하기에 앞서, 에너지 전환 정책의 구체적인 사항들을 확실한 근거에 기반해서 검토한 후 계획을 수립하는 것이 매우 중요한 일이다. 이 문제에 관해서 우리는 다음과 같은 점들을 검토하였다 (1) 한국이 처해 있는 기술적 경제적인 제약을 전제로 한 재생에너지원의 개발에 대한 정부의 역할, (2) 가스 발전으로 인해 발생할 수 있는 환경적이며 경제적인 문제점들, (3) 원전정책을 지속함으로써 얻을 수 있는 이점과 원전 유지에 대한 장애물. 위와 같은 세 가지 사항을 검토한 결과, 한국이 지니고 있는 지리적 경제적인 제약과 함께 탄소 배출로 인해 발생하는 비용까지 효과적으로 줄여야 한다는 점 등을 감안할 때 천연가스 발전으로 집중하겠다는 한국의 미래 에너지 정책은 친환경적이지 못함은 물론 경제적이지도 않기 때문에 적정한 비율의 재생에너지를 포함하는 원전 정책을 지속하는 것만이 현실적인 성공 가능성이 가장 높다고 보는 것이 우리의 결론이다.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.34 no.2
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• pp.106-111
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• 2006

Combustion test facility for liquid rocket engine using kerosene and liquid oxygen has been developed for the purpose of cooling and performance study. Test engine of thrust under 1.0 KN can be evaluated, and the real combustion test ensures a good operation of the combustion test facility. Combustion test facility will be modified to supply natural gas and liquefied natural gas as fuel and to give a regenerative cooling test.

• Journal of Ocean Engineering and Technology
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• v.31 no.6
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• pp.379-387
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• 2017

In this study, a pile-guide mooring system (PGMS) was designed for an offshore liquefied natural gas bunkering terminal (LNG-BT), which is an essential infrastructure for large LNG-fuelled ships. The PGMS consisted of guide piles to restrict five motions of the floater, except for heave, as well as a seabed truss structure to support the guide piles and foundation piles to fix the system to the seabed. Singapore port was considered for a case study because it is a highly probable ports for LNG bunkering projects. The wave height, current speed, and wind speed in Singapore port were investigated to calculate the environmental loads acting on the hull and PGMS. A load and resistance factor approach was used for the structural design, and a finite element analysis was performed for design verification. The steel usage of the PGMS was analyzed and compared with the material usage of a gravity-based structure under similar LNG capacity and water depth criteria. This paper also describes the water depth limit and wave conditions of the PGMS based on estimation of the initial investment and the present value profit difference. It suggests a suitable LNG-BT support system for various design conditions.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.27 no.1
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• pp.125-134
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• 2003

The present paper is concerned to the thermal analysis during the cool-down period of 138,000 m$^3$class GTT MARK-III membrane type LNG carrier servicing with LNG from the Middle East to Korea. It is the cool-down period that cools the insulation wall and the gas in LNG tank to avoid the thermal shock as the start of loading of -162$^{\circ}C$ LNG. For six hours of the standard cool-down period, the temperature of NG falls down from -4$0^{\circ}C$ to -13$0^{\circ}C$ and especially the mean temperature of the 1st barrier in the top side insulation wall falls down from -38.38$^{\circ}C$ to -122.42$^{\circ}C$ in case of IMO design condition. By the 3-D numerical calculation about the cargo tank and the cofferdam, the temperature variation in hulls and insulations is precisely predicted in this paper. And the mean temperature variation of gas is calculated as the function of the spraying rate by the heat balance model during the cool-down period.